Copper functionalized poly (acrylic acid-co-itaconic acid) nanohydrogel: Its antibacterial properties on oral pathogens and biocompatibility.

Although extensive efforts have been made to explore effective antibiotics, the development of antibiotics lags far behind the emergence of drug-resistant bacteria. Antimicrobial materials as an alternative strategy provide effective functions in aiding in relieving the dose of antibiotics. Herein, we report a novel antibacterial agent with high antibacterial effectivity and low toxicity, which is simply composed of a trace amount of Cu2+ ion and nanoscale biocompatible polymer poly (acrylic acid-co-itaconic acid) (PAI-Cu). The polymer shows greatly enhanced antibacterial activity against various Gram-positive and Gram-negative pathogens compared with equal concentrations of copper ion solution, yet shows nearly no toxicity towards human cells. The antibacterial performance and mechanism of copper ionized polymer hydrogel are evaluated in terms of multiple methods, towards various oral bacteria including Streptococcus mutans, Enterococcus faecalis, Lactobacillus acidophilus, Actinomycetes viscosus, Porphyromonas gingivalis, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, and Prevotella intermedia. Bacterial cell membrane and wall damage caused by PAI-Cu nanohydrogel should be regarded as an important antibacterial mechanism. Moreover, PAI-Cu nanohydrogel, as the role of catalytic active center, can activate the surrounding oxygen, and generate hydroxyl radical (·OH), which can destroy the proliferation ability of microbial cells. We suggest that PAI-Cu nanohydrogel is a promising antibacterial agent against dental pathogens and beyond.

Evaluation of 3D-printed oval root canal preparation by small field-of-view cone beam CT and computer-aided technique / 口腔疾病防治

Objective@# To evaluate the effect of 3D-printed oval root canal preparation by using small field-of-view cone beam CT (CBCT) combined with computer-aided technologies.@*Methods@#An extracted tooth with a suitable single oval canal was selected by small field-of-view CBCT scanning. Three-dimensional (3D)-printed resin teeth were obtained based on the CBCT data after data conversion and processing. 50 general dentists were selected to prepare the oval root canal of the resin teeth with X-Gold rotary Ni-Ti instruments. Small field-of-view CBCT was applied to scan the oval root canals before and after preparation. Then, computer-aided technologies were used to calculate and compare these CBCT data, analyzing the effects of oval root canal cleaning as well as the root canal deviation by 3D reconstruction and rendering of the images.@*Results @#Among the 50 cases, the mean unprepared area of the oval root canal wall was（56.20 ± 11.91）% and the mean maximum deviation distance of the root canal was（0.140 ± 0.041）mm. There was no correlation between root canal cleanliness and deviation (r=0.18, P=0.212).@*Conclusion @# Combined with small field-of-view CBCT and computer-aided technology, we can effectively quantitatively evaluate the root canal preparation effect.